ASUNTHA DEVI DEVA CHANDAR 20 A Cytomegalovirus

ASUNTHA DEVI DEVA CHANDAR 20 A Cytomegalovirus

Cytomegalovirus Family: Herpesviridae Subfamily: Betaherpesvirinae Genus: Cytomegalovirus

Morphology: Virions enveloped; slightly pleomorphic; spherical; 120 -200 nm in diameter. Surface projections of envelope distinct; spikes; dispersed evenly over all the surface. Nucleocapsids isometric. Nucleocapsid surrounded by the tegument that consists of globular material which is frequently asymmetrically distributed and may be variable in amount. Nucleocapsids sometimes penetrated by stain (although intact envelope impermeable to stain); 100 -110 nm in diameter. Symmetry icosahedral. Nucleocapsids appear to be angular. Surface capsomer arrangement obvious. 162 capsomers per nucleocapsid (capsomeres hexagonal in cross-section with a hole running half-way down the long axis). Core consists of a fibrillar spool on which the DNA is wrapped. The ends of the fibers are anchored to the underside of the capsid shell. Incomplete virus particles often present; they are capsids lacking the envelope.

Cytomegalovirus, or CMV, is a very common virus. People are usually infected by the time they are 2 years old or during their teenage years and carry the virus for life (usually in a dormant or inactive state). The majority of adults carry the virus by the time they are 40 years of age. Many people are infected with CMV and don't even know it because the virus rarely causes symptoms and usually does not cause long-term problems. However, CMV can cause problems in people who have weak immune systems and in a newborn if the mother gets the infection during pregnancy.

CMV gets into body fluids, such as saliva, blood, urine, semen and breast milk. A person is able to transmit (or "shed") the virus to others only when it is active in his or her system (not dormant). It can be spread from one person to another through sexual contact and contact with blood and other body fluids. CMV can rarely be transmitted by blood transfusion or organ transplantation. In child care centers, as many as 70% of children ages 1 to 3 can shed the virus. Careful, frequent hand washing with soap and water may help prevent the spread of CMV.

Symptoms Usually, CMV does not cause symptoms or only causes mild symptoms. A few people will have symptoms that are similar to mononucleosis. Symptoms of CMV can include: Sore throat Swollen lymph nodes (lymph glands) Fever Headache Fatigue Weakness Muscle aches Loss of appetite

People who have weakened immune systems due to conditions like human immunodeficiency virus (HIV) or because they received an organ transplant and are taking immunosuppressant medicines may have severe symptoms. (Immunosuppressant medicines are medicines that lower or suppress the immune system. ) Symptoms of severe CMV include: Blindness Pneumonia Diarrhea Bleeding ulcers in the esophagus (windpipe) or intestines Inflammation of the brain (encephalitis) Seizures

If a pregnant woman transmits CMV to her unborn baby, miscarriage, stillbirth or death of the newborn may occur. Newborns who survive are at an increased risk for hearing loss and mental retardation. However, only 1% of newborns who are infected with CMV during pregnancy experience problems from the virus. Most are born healthy, or with only mild CMV symptoms

diagnose CMV is more likey to cause vision problems in people who have weakened immune systems, so if you have conditions such as HIV or AIDS, your doctor may recommend that you visit an eye doctor to find out whether the virus has infected your eyes. Be sure to let your doctor know if you are having any painless blurring of your vision, "floaters" only in one eye, light flashes or areas of blindness. You should also let your doctor(s) know if you are experiencing frequent shortness of breath with flu-like symptoms, or if you are having problems hearing.

Treatment Cytomegalovirus vaccines are still in the research and development stage. For otherwise healthy people, CMV usually doesn't require treatment. If your immune system is weakened, your doctor may use one of several different medicines to treat CMV infection. However, because CMV is a virus, regular antibiotics won't work against it. Antiviral drugs are usually prescribed, which slows the virus down (but cannot cure CMV).

If you are pregnant, your doctor may want to test you for CMV to determine if there is a risk for your unborn baby. If you do carry the virus, your doctor may suggest a test called amniocentesis, which collects a sample of the amniotic fluid for testing. It can help determine whether your unborn baby has CMV. If you are pregnant and your baby has CMV, you doctor will likely check your baby once he or she is born for any problems or birth defects so they can be treated early. Treatable symptoms in newborns include pneumonia, hearing loss and inflammation of the eye.

Prevention Currently, there is no vaccine to prevent CMV infection. For those who have close contact with children, especially pregnant women or women who might become pregnant, hand washing is effective at reducing the risk of infection, as are not sharing eating utensils with young kids and avoiding intimate contact with anyone who has a CMV infection. A mother who has a CMV infection shouldn't stop breastfeeding — the benefits of breastfeeding are believed to outweigh the risks of passing CMV to the baby, who is unlikely to develop any symptoms if infected.

For organ-transplant patients who are at risk of getting CMV from a transplanted organ, preventive therapies are available. Blood banks have certain screening and processing procedures that help to prevent CMV from being passed in blood products.